Conventionally, in a case where a product such as an electronic device or the like is packaged by using a packaging box, it is a general method to dispose a cushioning material, which cushions external impact and vibration during transportation, between the product (packaged article) and the packaging box such as a cardboard case or the like. As the cushioning material, there are cushioning materials and the like used such as a folded cardboard, a recyclable pulp-molded cushioning material that uses old paper.
In the meantime, in a case where the packaging box is overturned or is transported in the overturned state when transporting or storing the product packaged in the packaging box, impact is cushioned by the cushioning material, but some impact is conducted to inside. Because of this, there is a case where the packaging box is not broken and only the inside product is broken. In such a case, the breakage of the product is not confirmed until the packaging box is opened. Accordingly, it is difficult to determine whether the breakage of the product occurred during the production or occurred when delivering or storing.
Accordingly, a patent literature 1 discloses a cushioning material with an impact sensor that includes a supersaturated solution, a first containing material and a second containing material that contain the solution, wherein upon being subjected to external force such as impact, vibration and the like, the solution changes its state visually to allow visual confirmation of being subjected to the external force.